COMPARISON OF HEART-RATE AND PHYSICAL-ACTIVITY RECALL WITH DOUBLY LABELED WATER IN OBESE WOMEN

Accurate methods of estimating total daily energy expenditure (TDEE) t hat are inexpensive and differentiate activities of varying intensitie s are needed in obesity research. We compared minute-by-minute heart r ate (HR) monitoring and the 7-d physical activity recall (PAR) questio nnaire with doubly labeled water (DLW) for the measurement of TDEE and physical activity in 14 obese women (45% +/-: 4% fat, mean +/- SD) be fore and during 12 wk of weight reduction. TDEE was measured over 2 wk by DLW. HR monitoring was conducted for 3 d, with individual VO2/HR c alibrations applied to HR data above 3 METs. PAR revealed the amount o f time spent in sleep, moderate, hard, and very hard activities during 1 wk, with time spent in light activities determined by difference. M ean TDEE values, expressed as the % difference from DLW, prior to weig ht loss were -5.2 +/- 10.8% by HR and 3.4 +/- 14.4 by PAR, and during the diet were +0.9 +/- 14.1% by HR and +0.9 +/- 14.7% by PAR. Individu al variability was high for both HR (-24.0 to +25.6%) and PAR (-27.4 t o +36.2%). Energy expended in physical activity prior to weight loss w ere 3.97 +/- 1.23 MJ.d(-1) by DLW, 3.91 +/- 0.90 by HR, and 4.79 +/- 0 .95 by PAR. During weight loss, physical activity values by DLW, HR, a nd PAR were 4.31 +/- 1.18, 4.84 +/- 2.22, and 4.64 +/- 1.06 MJ.d(-1) r espectively. In summary, HR and PAR accurately assessed TDEE and physi cal activity for the group, but individual variability was high.